Styrene foam is widely used to pack, among others, electric or electronic products, in corrugated cartons. This use of styrene foam, however, is a waste of valuable material when we consider the material is derived from limited natural resources, or petroleum. Also, disposing of packings of styrene foam causes not a few troublesome problems. So we should avoid using styrene foam as such packings and instead should use other suitable material for the same purpose. Actually, then, packings of corrugated paper is also used for this purpose, and the use of this material as such packings should be much more encouraged since this material does not cause similar serious problems to styrene foam. The most widely used packings of corrugated paper are block-shaped packings produced by bonding sheets of corrugated paper together. These packings, however, have to be prepared in addition to a corrugated carton in which to pack a product. Also, it takes much time and trouble to prepare these packings. Also, these block-shaped packings take up a lot of space and are therefore awkward to move or carry.